Haemocytometer and method of making the same



Nov. 20 1923. 1,474,812 E. D. BROOKER HAEMOCYTOMETER AND METHOD OFMAKING THE SAME Filed Jan. 192s avwewtoz 9. mm.-

Patented Nov. 20, 1923.

PATENT OFFICE.

EUGENE D. BROOKEB, OF NEW YORK, N. Y.

HEMOCYTOMETER AND METHOD OF MAKING THE SAME.

, Application filed January 2, 1923. Serial No. 610,219.

To all whom it may concern:

Be it known that I, EUGENE D. BROOKER, a citizen of the United States,and a resident of the city, county, and State of New York, have inventedcertain new and useful Improvements in Haemocytometers and Methods ofMaking the Same, of which the following is a specification.

My invention relates to haemocytometers or instruments used for makingcorpuscle counts. of the blood, for making bacteria counts, and forsimilar purposes. Heretofore, these instruments have usually been madeof glass and comprised a base, a cenl6 tral table and side tables ateach side thereof, the side tables rising one tenth milli meter abovethe plane of the center table so that when the slide is placed on thetables there will be a space between the under sur- 80 face of the slideand the top surface of the central table of one tenth millimeter indepth to form the counting chamber. Cross lines are generally placed onthe center table within which the number of corpuscles 26 or bacteriaare counted under a microscope.

There are gutters formed between the several tables and sometimes acrossthe central table, in which any excess fluid under test may run ofiwithout reaching the top sur- 30 faces of the side tables. Heretofore,these, instrumentshave been made in two general ways. One has been tomake the base and the tables separately and to then cement the tables inplace on the base with Canada hal- 86 sam. The objection to this methodhas been that the liquids used for cleaning the instruments oftendissolved the balsam and loosened the tables, or sometimes a knock orjar loosened the tables, either detaching them entirely or looseningthem enough to destroy the accuracy of the instrument. The other methodhas been to mill out a solid block of glass to form the tables andgutters; and the objection to this method is that of expense althoughthe instrument is otherwise superior to those made under the firstmethod.

The object of my invention is to provide a haemocytometer having thepermanency or ruggedness of those made under the last described methodbut which may be produced at a much lower cost, in fact at a cost nearlyas low as those made under the cementing process. My invention theretorerelates to the method of making these instruments and to the productproduced un-' der this method.

In the drawing forming part of this application,

Figure l is a sectional view of a haemocytometer embodying my inventionin one of its forms,

Figures 2 and 3 are similar views showingl my invention in other forms,and

igure 4 is a plan view of all the several forms.

In the practice of the method of making my improved haemocytometer Iprovide a base which is suitably ground off on its faces, and which baseis preferably of harder glass than that of which the tables are made:and on this base one or more of the tables are attached permanently byfusing the table to the base. If the table ismade of softer glass thanthebase and these are subjected to fusing heat the table will softenquicker than the base and fusion will take place without distortion ofthe base. In one form of my invention I fuse a relatively thick table tothe base and then grind 0 down the tables to the desired thicknessbecause if a very thin table member were subjected to the fusing heat itwould warp too much; whereas, if it is thick this will not occur; andthe grinding down also removes 35 any irregularity in the table. Inanother form I employ relatively thick tables and seat them in channelsin the base and then fuse them to the base. But in all cases I fuse someor all of the tables to the base. This makes the base and tablepractically one piece so that the use of acids or solvents will notloosen or separate the table and base, nor will shocks.

Referring first to the construction shown in Figure 1 where theinstrument is shown on an enlarged scale, there is a base 1 of 7 glassconsisting of a flat plate ground par allel on'its opposite surfaces 2,3. On this base I have mounted three tables comprising a center table 4on which a single or double counting scale or cross-line mark laterallyapart asshown and parallel to, each other upon the base 1- and the basewith these tables resting thereon are subjected to just suflicient heatto cause the tables and I p I I, I I I face of the center table 21. Inthis con- In this form of any invention thecenterf base to fuse and forman integral body, I

table 4,: after the base and side tables have been annealed, is placedupon the base and is I attached thereto bycement or Canada balsam. Thecenter table is so placed as toleave gutters 1O, 11 between it. and theside tables for excess liquid under test to flow off from the countingchamber. The side tables 6, 7 arethenground down on their top surfacesand polished, removing the material indicate'dbythe dotted 'lines, 8, 9until the top surfaces 12' of these tables are slightly above the planeof the top 13 of the central table 4. Then if an ordinary slip or slide(not shown) is placed upon the side tables 6, 7 there will be a slightspace, generally one tenth millimeter, between the cen-' tertablesurface .13, and the under surface of the.slide,forming the countingchamber to be occupied by theblood or other fluid under test. As thecenter table lies between the side. tables'6, 7 ,it is more or. lessprotected against displacement from a blow .7 by them. The constructionis superlor to one in which all thetables are cemented to the basevalthough inferior in some respects to some ofthe other forms to bedescribed.

In. Figure 2 I have'shown 'a device in which noneof the three tables'iscemented. In this construction I first. provide-a base 1 'which issomewhat thicker than the final base-is tobe and the base isthen groundor otherwise treated to remove the portions shown by'dotted line 14.This will leavethe final base with a central raised member,

15 integral therewith to constitute the central table. The side tables16, 17 of greater thickness than is, ultimately required, are

placed upon the base in spaced, parallel relation, as shown, to formgutters 10, 11 between them and these side tables arethen fused to thebase by being subjected to sufiicient heat to fuse theseparts together.

The portions of these; side tables represented in the dotted lines 18are then ground off to reduce the tops of these tables to a planeslightly above the plane of the center table '15. I In the finishedarticle the basc and all tables will be integraL In the constructionshown in Figure 3 a relatively thick base 1 is milled or ground out toprovide cross recesses 19, 20 sufiiciently'wide to form the gutters 10,11 and sockets for the side tables. Thismilling or grinding leaves acenter table 21 between the I shown in dotted lines 24 leaving the topsurfaces'ju'st above the plane of the top surstruction alltables'be'come integraliwith the base. K V V r In Figure fl it will beseenthatjthe top appearance "of all forms may be the same and Ipreferto,run the several table's out to the full width of the base and then grindthe edges 31, 32 of'the base and the ends of the several tables off evenat one time. In all forms the center table'may have a single set ofcross lines 5 or, in accordance with common practice the center tablemay have two sets of cross lines as indicated by dotted lines 33, 3a andthe center table'may have the two gutters 35, 36, cut crosswisetherethrough as indicated by dotted lines. In the'latter form, separatespecimens maybe examined under each set. of crosslines and the gutters35, 36 will prevent one 'specimen from flowing int the other across thecenter table, practice. I V v I Having described. my invention whatIclaim is: v. I 1. The methodof making 'heemocytome- This v conformspresent ters, which consists of providing a base,

placing thereon blocks or strips to form,

3 tables for the purpose set forth, and infusing said base and saidtable members together in an integral construction.

2. The method of making haemocytometers having a central table.andsidetables,

which consists in providing aIbase with a center table, in placingrelatively thick; blocks, or strips on said base, in fuslng said baseand said blocks together in an integral mass-and in then considerablyreducing the height of said blocks by removing material from the topsthereof for the purpose set fOI'th. I;

3. A haemocytometer comprising a base and tables projecting abovesaidbase, said tables being'formed of separate blocks of material unitedwith said base by fusing ghei basejand blocks together in an integral 0y;

integral, center table proje'ctingabove the 4. A heemocytometercomprising a base. i I having portions thereof removed to leave an gartable and formed by blocks fused to said ase.

5. A heemocytometer comprising a base having spaced recesses formedtherein to 5 leave an intermediate projection forming a center table,and side tables spaced from said center table and formed by blocksinserted in said recesses and each having a plurality of sides fused tothe base at the side walls of said recesses.

Signed at the city, county and State of New York, this 22nd day ofNovember 1922.

EUGENE D. BROOKER.

